Macroalgal associations of motile epifaunal invertebrate communities on coral reefs

Roff, George, Wabnitz, Colette C. C., Harborne, Alastair R. and Mumby, Peter J. (2013) Macroalgal associations of motile epifaunal invertebrate communities on coral reefs. Marine Ecology, 34 4: 409-419. doi:10.1111/maec.12040

Author Roff, George
Wabnitz, Colette C. C.
Harborne, Alastair R.
Mumby, Peter J.
Title Macroalgal associations of motile epifaunal invertebrate communities on coral reefs
Journal name Marine Ecology   Check publisher's open access policy
ISSN 0173-9565
Publication date 2013-01-01
Sub-type Article (original research)
DOI 10.1111/maec.12040
Volume 34
Issue 4
Start page 409
End page 419
Total pages 11
Place of publication Berlin, Germany
Publisher Wiley-Blackwell
Language eng
Subject 2303 Ecology
Formatted abstract
Small grazing motile epifaunal invertebrates play an important ecosystem role on coral reefs, influencing both the abundance and composition of macroalgal communities and acting as a key food source for a range of predatory fishes. The first aim of this study was to investigate the associations between motile epifaunal communities and four common macroalgal species (Lobophora variegata, Dictyota divaricata, Microdictyon marinum and Halimeda opuntia) on fore-reef environments in the Exuma Cays (Bahamas, wider Caribbean). Secondly, we investigated the implications of the well documented rise of Caribbean macroalgal cover on invertebrate densities by surveying sites inside and outside the Exuma Cays Land and Sea Park (ECLSP), where increases in parrotfish grazing intensity inside the marine reserves have led to reductions in macroalgal cover. Therefore, surveys compared similar reefs with significantly different macrolagal cover. Comparisons between macroalgal species revealed a four to fivefold difference in motile epifaunal densities per unit volume of macroalgae. Post-hoc tests revealed that this difference was significant only for Lobophora, with no difference observed among the other species. As macroalgae provide both a refuge from predation and a food source for grazing epifauna, the higher densities of epifauna observed in Lobophora may be attributed to either refuge from visual predators through morphological features (high cover of overlapping blades close to the substrate) or lack of palatability for parrotfish grazing, providing a more stable refuge. Our results revealed no significant differences in diversity, density or community structure of motile epifauna per unit volume of macroalgae between sites inside and outside the ECLSP. Since canopy height and invertivore biomass did not vary systematically across reserve boundaries, this suggests that algal cover does not affect the density of epifaunal invertebrates. However, areal cover was consistently higher for all macroalgal species at sites outside the ECLSP than those inside the reserve. Therefore, when scaled by aerial cover of macroalgae, total abundance of epifauna was twofold higher outside the ECLSP. We suggest that the increasing abundance of macroalgae on Caribbean reefs may be having dramatic effects on epifaunal invertebrate populations and potentially their ecological functions. 
Keyword Bahamas
Exuma Cays Land and Sea Park
Marine protected area (MPA)
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2014 Collection
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